This invention relates, in general, to input/output processing of a computing environment, and in particular, to virtual processing associated with adapters of the computing environment.
A computing environment may include one or more types of input/output devices, including various types of adapters. One type of adapter is a Peripheral Component Interconnect (PCI) or Peripheral Component Interconnect express (PCIe) adapter. This adapter includes one or more address spaces used in communicating data between the adapter and the system to which the adapter is attached.
In some systems, a portion of an address space of the central processing unit (CPU) coupled to the adapter is mapped to an address space of the adapter enabling CPU instructions that access storage to directly manipulate the data in the adapter's address space. This mapping of address spaces is sometimes referred to as memory-mapped I/O.